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Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_conv_fast_q31.c')
-rw-r--r-- | DSP_Lib/Source/FilteringFunctions/arm_conv_fast_q31.c | 577 |
1 files changed, 577 insertions, 0 deletions
diff --git a/DSP_Lib/Source/FilteringFunctions/arm_conv_fast_q31.c b/DSP_Lib/Source/FilteringFunctions/arm_conv_fast_q31.c new file mode 100644 index 0000000..4111a1e --- /dev/null +++ b/DSP_Lib/Source/FilteringFunctions/arm_conv_fast_q31.c @@ -0,0 +1,577 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* Project: CMSIS DSP Library +* Title: arm_conv_fast_q31.c +* +* Description: Q31 Convolution (fast version). +* +* Target Processor: Cortex-M4/Cortex-M3 +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* - Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* - Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in +* the documentation and/or other materials provided with the +* distribution. +* - Neither the name of ARM LIMITED nor the names of its contributors +* may be used to endorse or promote products derived from this +* software without specific prior written permission. +* +* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +* POSSIBILITY OF SUCH DAMAGE. +* -------------------------------------------------------------------- */ + +#include "arm_math.h" + +/** + * @ingroup groupFilters + */ + +/** + * @addtogroup Conv + * @{ + */ + +/** + * @param[in] *pSrcA points to the first input sequence. + * @param[in] srcALen length of the first input sequence. + * @param[in] *pSrcB points to the second input sequence. + * @param[in] srcBLen length of the second input sequence. + * @param[out] *pDst points to the location where the output result is written. Length srcALen+srcBLen-1. + * @return none. + * + * @details + * <b>Scaling and Overflow Behavior:</b> + * + * \par + * This function is optimized for speed at the expense of fixed-point precision and overflow protection. + * The result of each 1.31 x 1.31 multiplication is truncated to 2.30 format. + * These intermediate results are accumulated in a 32-bit register in 2.30 format. + * Finally, the accumulator is saturated and converted to a 1.31 result. + * + * \par + * The fast version has the same overflow behavior as the standard version but provides less precision since it discards the low 32 bits of each multiplication result. + * In order to avoid overflows completely the input signals must be scaled down. + * Scale down the inputs by log2(min(srcALen, srcBLen)) (log2 is read as log to the base 2) times to avoid overflows, + * as maximum of min(srcALen, srcBLen) number of additions are carried internally. + * + * \par + * See <code>arm_conv_q31()</code> for a slower implementation of this function which uses 64-bit accumulation to provide higher precision. + */ + +void arm_conv_fast_q31( + q31_t * pSrcA, + uint32_t srcALen, + q31_t * pSrcB, + uint32_t srcBLen, + q31_t * pDst) +{ + q31_t *pIn1; /* inputA pointer */ + q31_t *pIn2; /* inputB pointer */ + q31_t *pOut = pDst; /* output pointer */ + q31_t *px; /* Intermediate inputA pointer */ + q31_t *py; /* Intermediate inputB pointer */ + q31_t *pSrc1, *pSrc2; /* Intermediate pointers */ + q31_t sum, acc0, acc1, acc2, acc3; /* Accumulator */ + q31_t x0, x1, x2, x3, c0; /* Temporary variables to hold state and coefficient values */ + uint32_t j, k, count, blkCnt, blockSize1, blockSize2, blockSize3; /* loop counter */ + + /* The algorithm implementation is based on the lengths of the inputs. */ + /* srcB is always made to slide across srcA. */ + /* So srcBLen is always considered as shorter or equal to srcALen */ + if(srcALen >= srcBLen) + { + /* Initialization of inputA pointer */ + pIn1 = pSrcA; + + /* Initialization of inputB pointer */ + pIn2 = pSrcB; + } + else + { + /* Initialization of inputA pointer */ + pIn1 = pSrcB; + + /* Initialization of inputB pointer */ + pIn2 = pSrcA; + + /* srcBLen is always considered as shorter or equal to srcALen */ + j = srcBLen; + srcBLen = srcALen; + srcALen = j; + } + + /* conv(x,y) at n = x[n] * y[0] + x[n-1] * y[1] + x[n-2] * y[2] + ...+ x[n-N+1] * y[N -1] */ + /* The function is internally + * divided into three stages according to the number of multiplications that has to be + * taken place between inputA samples and inputB samples. In the first stage of the + * algorithm, the multiplications increase by one for every iteration. + * In the second stage of the algorithm, srcBLen number of multiplications are done. + * In the third stage of the algorithm, the multiplications decrease by one + * for every iteration. */ + + /* The algorithm is implemented in three stages. + The loop counters of each stage is initiated here. */ + blockSize1 = srcBLen - 1u; + blockSize2 = srcALen - (srcBLen - 1u); + blockSize3 = blockSize1; + + /* -------------------------- + * Initializations of stage1 + * -------------------------*/ + + /* sum = x[0] * y[0] + * sum = x[0] * y[1] + x[1] * y[0] + * .... + * sum = x[0] * y[srcBlen - 1] + x[1] * y[srcBlen - 2] +...+ x[srcBLen - 1] * y[0] + */ + + /* In this stage the MAC operations are increased by 1 for every iteration. + The count variable holds the number of MAC operations performed */ + count = 1u; + + /* Working pointer of inputA */ + px = pIn1; + + /* Working pointer of inputB */ + py = pIn2; + + + /* ------------------------ + * Stage1 process + * ----------------------*/ + + /* The first stage starts here */ + while(blockSize1 > 0u) + { + /* Accumulator is made zero for every iteration */ + sum = 0; + + /* Apply loop unrolling and compute 4 MACs simultaneously. */ + k = count >> 2u; + + /* First part of the processing with loop unrolling. Compute 4 MACs at a time. + ** a second loop below computes MACs for the remaining 1 to 3 samples. */ + while(k > 0u) + { + /* x[0] * y[srcBLen - 1] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* x[1] * y[srcBLen - 2] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* x[2] * y[srcBLen - 3] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* x[3] * y[srcBLen - 4] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* If the count is not a multiple of 4, compute any remaining MACs here. + ** No loop unrolling is used. */ + k = count % 0x4u; + + while(k > 0u) + { + /* Perform the multiply-accumulate */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* Store the result in the accumulator in the destination buffer. */ + *pOut++ = sum << 1; + + /* Update the inputA and inputB pointers for next MAC calculation */ + py = pIn2 + count; + px = pIn1; + + /* Increment the MAC count */ + count++; + + /* Decrement the loop counter */ + blockSize1--; + } + + /* -------------------------- + * Initializations of stage2 + * ------------------------*/ + + /* sum = x[0] * y[srcBLen-1] + x[1] * y[srcBLen-2] +...+ x[srcBLen-1] * y[0] + * sum = x[1] * y[srcBLen-1] + x[2] * y[srcBLen-2] +...+ x[srcBLen] * y[0] + * .... + * sum = x[srcALen-srcBLen-2] * y[srcBLen-1] + x[srcALen] * y[srcBLen-2] +...+ x[srcALen-1] * y[0] + */ + + /* Working pointer of inputA */ + px = pIn1; + + /* Working pointer of inputB */ + pSrc2 = pIn2 + (srcBLen - 1u); + py = pSrc2; + + /* count is index by which the pointer pIn1 to be incremented */ + count = 0u; + + /* ------------------- + * Stage2 process + * ------------------*/ + + /* Stage2 depends on srcBLen as in this stage srcBLen number of MACS are performed. + * So, to loop unroll over blockSize2, + * srcBLen should be greater than or equal to 4 */ + if(srcBLen >= 4u) + { + /* Loop unroll over blockSize2, by 4 */ + blkCnt = blockSize2 >> 2u; + + while(blkCnt > 0u) + { + /* Set all accumulators to zero */ + acc0 = 0; + acc1 = 0; + acc2 = 0; + acc3 = 0; + + /* read x[0], x[1], x[2] samples */ + x0 = *(px++); + x1 = *(px++); + x2 = *(px++); + + /* Apply loop unrolling and compute 4 MACs simultaneously. */ + k = srcBLen >> 2u; + + /* First part of the processing with loop unrolling. Compute 4 MACs at a time. + ** a second loop below computes MACs for the remaining 1 to 3 samples. */ + do + { + /* Read y[srcBLen - 1] sample */ + c0 = *(py--); + + /* Read x[3] sample */ + x3 = *(px++); + + /* Perform the multiply-accumulates */ + /* acc0 += x[0] * y[srcBLen - 1] */ + acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x0 * c0)) >> 32); + + /* acc1 += x[1] * y[srcBLen - 1] */ + acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x1 * c0)) >> 32); + + /* acc2 += x[2] * y[srcBLen - 1] */ + acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x2 * c0)) >> 32); + + /* acc3 += x[3] * y[srcBLen - 1] */ + acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x3 * c0)) >> 32); + + /* Read y[srcBLen - 2] sample */ + c0 = *(py--); + + /* Read x[4] sample */ + x0 = *(px++); + + /* Perform the multiply-accumulate */ + /* acc0 += x[1] * y[srcBLen - 2] */ + acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x1 * c0)) >> 32); + /* acc1 += x[2] * y[srcBLen - 2] */ + acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x2 * c0)) >> 32); + /* acc2 += x[3] * y[srcBLen - 2] */ + acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x3 * c0)) >> 32); + /* acc3 += x[4] * y[srcBLen - 2] */ + acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x0 * c0)) >> 32); + + /* Read y[srcBLen - 3] sample */ + c0 = *(py--); + + /* Read x[5] sample */ + x1 = *(px++); + + /* Perform the multiply-accumulates */ + /* acc0 += x[2] * y[srcBLen - 3] */ + acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x2 * c0)) >> 32); + /* acc1 += x[3] * y[srcBLen - 3] */ + acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x3 * c0)) >> 32); + /* acc2 += x[4] * y[srcBLen - 3] */ + acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x0 * c0)) >> 32); + /* acc3 += x[5] * y[srcBLen - 3] */ + acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x1 * c0)) >> 32); + + /* Read y[srcBLen - 4] sample */ + c0 = *(py--); + + /* Read x[6] sample */ + x2 = *(px++); + + /* Perform the multiply-accumulates */ + /* acc0 += x[3] * y[srcBLen - 4] */ + acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x3 * c0)) >> 32); + /* acc1 += x[4] * y[srcBLen - 4] */ + acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x0 * c0)) >> 32); + /* acc2 += x[5] * y[srcBLen - 4] */ + acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x1 * c0)) >> 32); + /* acc3 += x[6] * y[srcBLen - 4] */ + acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x2 * c0)) >> 32); + + + } while(--k); + + /* If the srcBLen is not a multiple of 4, compute any remaining MACs here. + ** No loop unrolling is used. */ + k = srcBLen % 0x4u; + + while(k > 0u) + { + /* Read y[srcBLen - 5] sample */ + c0 = *(py--); + + /* Read x[7] sample */ + x3 = *(px++); + + /* Perform the multiply-accumulates */ + /* acc0 += x[4] * y[srcBLen - 5] */ + acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x0 * c0)) >> 32); + /* acc1 += x[5] * y[srcBLen - 5] */ + acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x1 * c0)) >> 32); + /* acc2 += x[6] * y[srcBLen - 5] */ + acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x2 * c0)) >> 32); + /* acc3 += x[7] * y[srcBLen - 5] */ + acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x3 * c0)) >> 32); + + /* Reuse the present samples for the next MAC */ + x0 = x1; + x1 = x2; + x2 = x3; + + /* Decrement the loop counter */ + k--; + } + + /* Store the results in the accumulators in the destination buffer. */ + *pOut++ = (q31_t) (acc0 << 1); + *pOut++ = (q31_t) (acc1 << 1); + *pOut++ = (q31_t) (acc2 << 1); + *pOut++ = (q31_t) (acc3 << 1); + + /* Increment the pointer pIn1 index, count by 4 */ + count += 4u; + + /* Update the inputA and inputB pointers for next MAC calculation */ + px = pIn1 + count; + py = pSrc2; + + /* Decrement the loop counter */ + blkCnt--; + } + + /* If the blockSize2 is not a multiple of 4, compute any remaining output samples here. + ** No loop unrolling is used. */ + blkCnt = blockSize2 % 0x4u; + + while(blkCnt > 0u) + { + /* Accumulator is made zero for every iteration */ + sum = 0; + + /* Apply loop unrolling and compute 4 MACs simultaneously. */ + k = srcBLen >> 2u; + + /* First part of the processing with loop unrolling. Compute 4 MACs at a time. + ** a second loop below computes MACs for the remaining 1 to 3 samples. */ + while(k > 0u) + { + /* Perform the multiply-accumulates */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* If the srcBLen is not a multiple of 4, compute any remaining MACs here. + ** No loop unrolling is used. */ + k = srcBLen % 0x4u; + + while(k > 0u) + { + /* Perform the multiply-accumulate */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* Store the result in the accumulator in the destination buffer. */ + *pOut++ = sum << 1; + + /* Increment the MAC count */ + count++; + + /* Update the inputA and inputB pointers for next MAC calculation */ + px = pIn1 + count; + py = pSrc2; + + /* Decrement the loop counter */ + blkCnt--; + } + } + else + { + /* If the srcBLen is not a multiple of 4, + * the blockSize2 loop cannot be unrolled by 4 */ + blkCnt = blockSize2; + + while(blkCnt > 0u) + { + /* Accumulator is made zero for every iteration */ + sum = 0; + + /* srcBLen number of MACS should be performed */ + k = srcBLen; + + while(k > 0u) + { + /* Perform the multiply-accumulate */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* Store the result in the accumulator in the destination buffer. */ + *pOut++ = sum << 1; + + /* Increment the MAC count */ + count++; + + /* Update the inputA and inputB pointers for next MAC calculation */ + px = pIn1 + count; + py = pSrc2; + + /* Decrement the loop counter */ + blkCnt--; + } + } + + + /* -------------------------- + * Initializations of stage3 + * -------------------------*/ + + /* sum += x[srcALen-srcBLen+1] * y[srcBLen-1] + x[srcALen-srcBLen+2] * y[srcBLen-2] +...+ x[srcALen-1] * y[1] + * sum += x[srcALen-srcBLen+2] * y[srcBLen-1] + x[srcALen-srcBLen+3] * y[srcBLen-2] +...+ x[srcALen-1] * y[2] + * .... + * sum += x[srcALen-2] * y[srcBLen-1] + x[srcALen-1] * y[srcBLen-2] + * sum += x[srcALen-1] * y[srcBLen-1] + */ + + /* In this stage the MAC operations are decreased by 1 for every iteration. + The blockSize3 variable holds the number of MAC operations performed */ + + /* Working pointer of inputA */ + pSrc1 = (pIn1 + srcALen) - (srcBLen - 1u); + px = pSrc1; + + /* Working pointer of inputB */ + pSrc2 = pIn2 + (srcBLen - 1u); + py = pSrc2; + + /* ------------------- + * Stage3 process + * ------------------*/ + + while(blockSize3 > 0u) + { + /* Accumulator is made zero for every iteration */ + sum = 0; + + /* Apply loop unrolling and compute 4 MACs simultaneously. */ + k = blockSize3 >> 2u; + + /* First part of the processing with loop unrolling. Compute 4 MACs at a time. + ** a second loop below computes MACs for the remaining 1 to 3 samples. */ + while(k > 0u) + { + /* sum += x[srcALen - srcBLen + 1] * y[srcBLen - 1] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* sum += x[srcALen - srcBLen + 2] * y[srcBLen - 2] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* sum += x[srcALen - srcBLen + 3] * y[srcBLen - 3] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* sum += x[srcALen - srcBLen + 4] * y[srcBLen - 4] */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* If the blockSize3 is not a multiple of 4, compute any remaining MACs here. + ** No loop unrolling is used. */ + k = blockSize3 % 0x4u; + + while(k > 0u) + { + /* Perform the multiply-accumulate */ + sum = (q31_t) ((((q63_t) sum << 32) + + ((q63_t) * px++ * (*py--))) >> 32); + + /* Decrement the loop counter */ + k--; + } + + /* Store the result in the accumulator in the destination buffer. */ + *pOut++ = sum << 1; + + /* Update the inputA and inputB pointers for next MAC calculation */ + px = ++pSrc1; + py = pSrc2; + + /* Decrement the loop counter */ + blockSize3--; + } + +} + +/** + * @} end of Conv group + */ |